Troy Christensen's thesis
– Executive Summary –
Extreme heat is a major U.S. homeland security threat that will increase in the coming years. The Centers for Disease Control and Prevention (CDC) attributes an average of 1,220 deaths to extreme heat yearly, with preliminary fatality numbers from 2023 and 2024 being significantly higher.[1] Climate change and demographic trends will increase the threat of extreme heat in the future, with one study suggesting “heat-related mortality is projected to be more than double by the 2050s” compared to current levels.[2] In the wake of this increasing threat, many emergency managers and communities are not adequately prepared.[3] However, preparing for extreme heat and its potentially cascading impact in many parts of the country is overlooked as other risks dominate long-term planning within emergency management agencies. Formulating solutions to this complex problem is challenging, but recognizing extreme heat concerns and threats within the emergency management community will facilitate better planning and mitigation when extreme heat events occur.
This thesis analyzes the potential shocks of extreme heat on America’s emergency management community in the future. Specifically, the thesis focuses on future extreme heat impacts in Phoenix, Chicago, Seattle, and Atlanta. These cities represent a diverse cross-section of United States climates and, therefore, represent a much larger number of urban areas. The study employs a scenario-based approach for each city to determine the effects of extreme heat events in future global temperature increases of +1.5ºC, +2.0ºC, and +2.5ºC above pre-industrial levels. Research demonstrates that the frequency and severity of extreme heat events directly correlate with broader global temperature change scenarios used in this thesis.[4] Thus, an increase in extreme heat events will directly correlate with future global temperature increases.
Each warming scenario focuses on the expected impacts on FEMA community lifelines, representing vital functions of a community to ensure safety, security, and well-being. FEMA’s community lifelines correlate to a community’s response and recovery priorities after a natural disaster. Each “lifeline” represents a critical sector crucial to a community’s recovery, including safety/security, food/hydration/shelter, health/medical, energy, communications, transportation, hazardous materials, and water systems.[5] This thesis uses scenario planning to identify and evaluate the potential ramifications of future extreme heat events within a community based on FEMA community lifelines.
The analysis showed that all four cities included in the scenarios would likely see an increasing number of extreme heat events in the future, paired with an increase in event severity in future climates. This increase will be felt more strongly in temperate cities across the northern tier of the United States, where a combination of fewer mitigation measures (such as air conditioning) and lower acclimatization to hot temperatures paired with a more significant rate of change in frequency of extreme heat events will have the greatest impact on communities and, therefore, emergency managers. Negative public health consequences will remain the greatest threat from extreme heat events, and they will grow in all three climate scenarios of +1.5ºC, +2.0ºC, and +2.5ºC.
The scenarios showed that while some planning is individualized depending on each community, communities must plan for cascading events related to extreme heat. The two most important considerations during an extreme heat event will be maintaining electrical power and water service. While maintaining these two lifelines may seem like common sense, almost every other critical sector will also see massive disruption if these two sectors fail. The failure could also lead to a large loss of life during an extreme heat event, renewing the discussion about protecting our critical infrastructure and the need for closer collaboration between the utility industry and emergency management staff in planning efforts.
Based on the extreme heat scenarios and comparative analysis, the recommendations for emergency managers to consider when preparing for future extreme heat events include preparing for cascading impacts, creating heat-specific plans, focusing on all sectors instead of just public health, improving heat awareness and communication, and advocating for enhanced funding for extreme heat threats to address future concerns.
One of the primary findings in this thesis is the widespread risk of cascading events occurring during extreme heat events. These cascading events can range from power grid failures due to the overuse of electricity, to water shortages, to the greater potential for subsequent flooding events in the Midwest in the wake of heat episodes. Extreme heat is a deadly natural disaster, but it has the potential to be deadly at a much higher magnitude if other critical support systems fail. Extreme heat preparation and planning must focus on low-risk/high-impact events, which will become the high-risk/high-impact events of the future.
While emergency management planning efforts have improved over the years, much of the effort has gone into producing “All Hazards” plans. These plans are meant to reduce the need to create a separate document for different hazards or emergencies. One critique of this process is that it rarely includes the necessary detail to respond to an extreme heat event. Many All Hazards plans neglect to plan for cascading impacts, especially since extreme heat is a hazard rarely localized to a single community. These plans should include private-sector utilities and healthcare networks, water-consuming sectors such as irrigation districts, and disadvantaged communities that are sometimes neglected in community engagement processes.
Public health is still at the forefront of the extreme heat discussion, as many of the negative consequences that are experienced in these events are directly related to public health outcomes. This suggests that short-term planning and mitigation should still be focused on the health sector. In practice, this focus could look like increased outreach to vulnerable populations, such as those with cardiovascular or respiratory diseases, as well as socially isolated individuals who may not have transportation to travel to a cooling center. While the health sector is vital, it is also important not to put all of the focus on a single sector while ignoring other critical sectors that could have an equally large impact on a community should they be negatively affected.
Almost every extreme heat death is preventable, yet a combination of factors continues to lead to deaths every year. One recommendation is to incorporate universal standards to warn about extreme heat events in an easy-to-understand way. The recommendation also focuses on urging people-first messaging to reduce the use of scientific jargon and focus on the action an individual should take. Communication requires a trusted messenger to relay the information. The messenger could be a trusted advocate in a socially vulnerable community or a doctor for someone with a condition that makes them more vulnerable to heat. Although these campaigns are currently in place for some jurisdictions, many communities at most significant risk from deadly extreme heat events do not have public awareness campaigns.
Emergency managers must also rely on elected officials and official budgets for additional funding to support these initiatives, yet public officials often prioritize more pressing needs instead of funding for additional support during extreme heat events. Emergency managers must continue to improve extreme heat awareness with elected officials to ensure the officials are aware of more frequent and impactful future events and the potential for more staff and resources.
[1] “Extreme Heat and Your Health,” Extreme Heat, accessed September 22, 2023, https://www.cdc.gov/disasters/extremeheat/heat_guide.html; “AP Analysis Finds 2023 Set Record for US Heat Deaths, Killing in Areas That Used to Handle the Heat,” AP News, May 31, 2024, https://apnews.com/article/record-heat-deadly-climate-change-humidity-south-11de21a526e1cbe7e306c47c2f12438d; and Zahra Hirji and Preeti Soni, “No One Knows Exactly How Many People Are Dying from Extreme Heat,” Bloomberg, July 8, 2024, https://www.bloomberg.com/news/features/2024-07-08/how-many-people-have-died-from-extreme-heat-officials-struggle-to-track.
[2] Cunrui Huang et al., “Projecting Future Heat-Related Mortality under Climate Change Scenarios: A Systematic Review,” Environmental Health Perspectives 119, no. 12 (December 2011): 1683, https://doi.org/10.1289/ehp.1103456.
[3] Nicole A. Errett et al., “Survey of Extreme Heat Public Health Preparedness Plans and Response Activities in the Most Populous Jurisdictions in the United States,” BMC Public Health 23, no. 1 (2023): 9, https://doi.org/10.1186/s12889-023-15757-x; C. J. Gabbe et al., “Why and How Do Cities Plan for Extreme Heat?,” Journal of Planning Education and Research, 2021, 11, https://doi.org/10.1177/0739456X211053654; Brian Stone, Jr. et al., “Compound Climate and Infrastructure Events: How Electrical Grid Failure Alters Heat Wave Risk,” Environmental Science & Technology 55, no. 10 (2021): 6963, https://doi.org/10.1021/acs.est.1c00024; and Nicholas Kimutis, Tamara Wall, and Lyndsey Darrow, “Emergency Management Short Term Response to Extreme Heat in the 25 Most Populated U.S. Cities,” International Journal of Disaster Risk Reduction 100 (2024): 1–9, https://doi.org/10.1016/j.ijdrr.2023.104097.
[4] Alessandro Dosio et al., “Extreme Heat Waves under 1.5 °C and 2 °C Global Warming,” Environmental Research Letters 13, no. 5 (May 2018): 1–10, https://doi.org/10.1088/1748-9326/aab827.
[5] Federal Emergency Management Agency, “Community Lifelines,” Federal Emergency Management Agency, accessed October 24, 2023, https://www.fema.gov/emergency-managers/practitioners/lifelines.